Classifications

• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08F—MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
  • C08F110/00—Homopolymers of unsaturated aliphatic hydrocarbons having only one carbon-to-carbon double bond
  • C08F110/04—Monomers containing three or four carbon atoms
  • C08F110/06—Propene
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08F—MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
  • C08F10/00—Homopolymers and copolymers of unsaturated aliphatic hydrocarbons having only one carbon-to-carbon double bond
  • C08F10/04—Monomers containing three or four carbon atoms
  • C08F10/06—Propene
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08F—MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
  • C08F2/00—Processes of polymerisation
  • C08F2/001—Multistage polymerisation processes characterised by a change in reactor conditions without deactivating the intermediate polymer
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08F—MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
  • C08F4/00—Polymerisation catalysts
  • C08F4/42—Metals; Metal hydrides; Metallo-organic compounds; Use thereof as catalyst precursors
  • C08F4/44—Metals; Metal hydrides; Metallo-organic compounds; Use thereof as catalyst precursors selected from light metals, zinc, cadmium, mercury, copper, silver, gold, boron, gallium, indium, thallium, rare earths or actinides
  • C08F4/60—Metals; Metal hydrides; Metallo-organic compounds; Use thereof as catalyst precursors selected from light metals, zinc, cadmium, mercury, copper, silver, gold, boron, gallium, indium, thallium, rare earths or actinides together with refractory metals, iron group metals, platinum group metals, manganese, rhenium technetium or compounds thereof
  • C08F4/62—Refractory metals or compounds thereof
  • C08F4/64—Titanium, zirconium, hafnium or compounds thereof
  • C08F4/647—Catalysts containing a specific non-metal or metal-free compound
  • C08F4/649—Catalysts containing a specific non-metal or metal-free compound organic
  • C08F4/6491—Catalysts containing a specific non-metal or metal-free compound organic hydrocarbon
  • C08F4/6492—Catalysts containing a specific non-metal or metal-free compound organic hydrocarbon containing aliphatic unsaturation
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08F—MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
  • C08F4/00—Polymerisation catalysts
  • C08F4/42—Metals; Metal hydrides; Metallo-organic compounds; Use thereof as catalyst precursors
  • C08F4/44—Metals; Metal hydrides; Metallo-organic compounds; Use thereof as catalyst precursors selected from light metals, zinc, cadmium, mercury, copper, silver, gold, boron, gallium, indium, thallium, rare earths or actinides
  • C08F4/60—Metals; Metal hydrides; Metallo-organic compounds; Use thereof as catalyst precursors selected from light metals, zinc, cadmium, mercury, copper, silver, gold, boron, gallium, indium, thallium, rare earths or actinides together with refractory metals, iron group metals, platinum group metals, manganese, rhenium technetium or compounds thereof
  • C08F4/62—Refractory metals or compounds thereof
  • C08F4/64—Titanium, zirconium, hafnium or compounds thereof
  • C08F4/65—Pretreating the metal or compound covered by group C08F4/64 before the final contacting with the metal or compound covered by group C08F4/44
  • C08F4/652—Pretreating with metals or metal-containing compounds
  • C08F4/654—Pretreating with metals or metal-containing compounds with magnesium or compounds thereof
  • C08F4/6543—Pretreating with metals or metal-containing compounds with magnesium or compounds thereof halides of magnesium
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
  • C08L23/00—Compositions of homopolymers or copolymers of unsaturated aliphatic hydrocarbons having only one carbon-to-carbon double bond; Compositions of derivatives of such polymers
  • C08L23/02—Compositions of homopolymers or copolymers of unsaturated aliphatic hydrocarbons having only one carbon-to-carbon double bond; Compositions of derivatives of such polymers not modified by chemical after-treatment
  • C08L23/10—Homopolymers or copolymers of propene
  • C08L23/12—Polypropene
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
  • C08L23/00—Compositions of homopolymers or copolymers of unsaturated aliphatic hydrocarbons having only one carbon-to-carbon double bond; Compositions of derivatives of such polymers
  • C08L23/02—Compositions of homopolymers or copolymers of unsaturated aliphatic hydrocarbons having only one carbon-to-carbon double bond; Compositions of derivatives of such polymers not modified by chemical after-treatment
  • C08L23/10—Homopolymers or copolymers of propene
  • C08L23/14—Copolymers of propene
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08F—MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
  • C08F210/00—Copolymers of unsaturated aliphatic hydrocarbons having only one carbon-to-carbon double bond
  • C08F210/04—Monomers containing three or four carbon atoms
  • C08F210/06—Propene
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08F—MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
  • C08F210/00—Copolymers of unsaturated aliphatic hydrocarbons having only one carbon-to-carbon double bond
  • C08F210/16—Copolymers of ethene with alpha-alkenes, e.g. EP rubbers
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08F—MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
  • C08F2500/00—Characteristics or properties of obtained polyolefins; Use thereof
  • C08F2500/05—Bimodal or multimodal molecular weight distribution
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08F—MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
  • C08F2500/00—Characteristics or properties of obtained polyolefins; Use thereof
  • C08F2500/12—Melt flow index or melt flow ratio
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08F—MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
  • C08F2500/00—Characteristics or properties of obtained polyolefins; Use thereof
  • C08F2500/17—Viscosity
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
  • C08L2205/00—Polymer mixtures characterised by other features
  • C08L2205/02—Polymer mixtures characterised by other features containing two or more polymers of the same C08L -group
  • C08L2205/025—Polymer mixtures characterised by other features containing two or more polymers of the same C08L -group containing two or more polymers of the same hierarchy C08L, and differing only in parameters such as density, comonomer content, molecular weight, structure

Definitions

• the present invention is directed to a new process with increased productivity for the manufacture of polypropylene having a low ash content.
• Polypropylene is used in many applications and is for instance the material of choice in the field of film capacitors as its chain lacks any kind of polar groups which orient under electrical field stress.
• polypropylene intrinsically possesses a low loss factor and high volume resistivity.
• These properties combined with a relatively high dielectric constant and self-healing character in the capacitor as well as good mechanical properties, like high melting temperature and high stiffness, make polypropylene so valuable in this technical field.
• a Ziegler-Natta catalyst typically the dielectric film made from such a polypropylene contains considerable amounts of polar residues, like chlorine, aluminium, titanium, magnesium or silicon originating from the used Ziegler-Natta catalyst.
• washing liquid typically used comprises organic hydrocarbon solvents having polar groups, like hydroxyl groups, e.g. propanol.
• the high amount of residues is caused by several factors, wherein productivity plays a central role.
• productivity of the used catalyst is high during the polymerization process, lower amounts of catalyst can be employed and thus the amount of undesired residues can be reduced.
• the object of the present invention is to provide a process which enables a skilled person to produce a polypropylene with high productivity by keeping the residue content in the polypropylene low even without the need to apply a troublesome washing step.
• the finding of the present invention is to use a low ratio of catalyst feed rate to propylene (C3) feed rate in a first polymerization reactor (R1) in order to surprisingly increase catalyst productivity.
• a Ziegler Natta catalyst with a very balanced mol-ratio of co-catalyst (Co) to external donor (ED) [Co/ED] and/or of co-catalyst (Co) to transition metal (TM) [Co/TM] is used.
• the present invention relates to a process for the preparation of a polypropylene (PP) in a sequential polymerization process comprising at least two polymerization reactors (R1 and R2) connected in series, wherein
• the polymerization in the at least two polymerization reactors (R1 and R2) takes place in the presence of a Ziegler-Natta catalyst (ZN-C), and said Ziegler-Natta catalyst (ZN-C) comprises
• the mol-ratio of co-catalyst (Co) to external donor (ED) [Co/ED] is in the range of above 10 to below 25 and/or the mol-ratio of co-catalyst (Co) to transition metal (TM) [Co/TM] is in the range of above 100 to below 200,
• the process according to the present invention preferably includes a sequential polymerization process comprising at least two reactors (R1 and R2), preferably at least three polymerization reactors (R1, R2 and R3), connected in series.
• the temperature is at least in one of the at least two polymerization reactors (R1 and R2), preferably at least in one of the at least three polymerization reactors (R1, R2 and R3), more preferably in all three reactors (R1, R2 and R3), in the range of 50° C. to 130° C.
• the polypropylene (PP-A) produced in the first polymerization reactor (R1) has a melt flow rate (MFR 2 ) measured according to ISO 1133 higher than the melt flow rate (MFR 2 ) of the polypropylene (PP) obtained as the final product.
• a pre-polymerization reactor (PR) upstream to the first polymerization reactor (R1) is additionally used, wherein said Ziegler-Natta catalyst (ZN-C) is present in the pre-polymerization reactor (PR). It is preferred that pre-polymerization is carried out in the pre-polymerization reactor (PR) at a temperature of 0 to 60° C.
• ethylene (C2) in addition to propylene (C3) is fed to said pre-polymerization reactor (PR) in a C2/C3 feed ratio of 0.5 to 10.0 g/kg; and/or in a manner to accomplish a C2/C3 ratio in the pre-polymerization reactor (PR) of 0.5 to 5.0 mol/kmol.
• a polypropylene (PP) produced according to the inventive process using low catalyst feed rate to propylene (C3) feed rate in the first polymerization reactor (R1) has a low residue content. Further the productivity of the applied catalyst under these conditions is very high. It has further been found that by carrying out the inventive process such that the melt flow rate MFR 2 of the polypropylene (PP-A) produced in the first polymerization reactor (R1) is higher than the melt flow rate (MFR 2 ) of the polypropylene (PP) obtained as the final product further increases productivity and thus reduces the residue content in the obtained polypropylene (PP). In addition, it has been found that by additionally using an ethylene feed during pre-polymerization and using a specific Ziegler-Natta catalyst (ZN-C) productivity can be further increased and residue content can be reduced.
• ZN-C Ziegler-Natta catalyst
• the present invention is also directed to a propylene homopolymer (H-PP) having
• propylene homopolymer (H-PP) is further defined by
• the process according the present invention comprises at least two polymerization reactors (R1 and R2), more preferably at least three polymerization reactors (R1, R2 and R3). In one preferred embodiment the process according the present invention consists of three polymerization reactors (R1, R2 and R3).
• a pre-polymerization step in a pre-polymerization reactor is applied prior to the (main) polymerization in the at least two polymerization reactors (R1 and R2), preferably prior to the (main) polymerization in the at least three polymerization reactors (R1, R2 and R3), more preferably prior to the (main) polymerization in the three polymerization reactors (R1, R2 and R3).
• polymerization is carried out in the at least two polymerization reactors (R1 and R2), preferably in the at least three polymerization reactors (R1, R2 and R3), more preferably in the three polymerization reactors (R1, R2 and R3), only without the use of pre-polymerization.
• All reactors i.e. the optional pre-polymerization reactor (PR) and the other polymerization reactors arranged downstream to the polymerization reactor (PR), i.e. the at least two polymerization reactors (R1 and R2), like the at least three polymerization reactors (R1, R2 and R3), are connected in series.
• PR pre-polymerization reactor
• R1 and R2 the at least two polymerization reactors
• R1, R2 and R3 like the at least three polymerization reactors
• pre-polymerization indicates that this is not the main polymerization in which the instant polypropylene (PP) is produced.
• at least two polymerization reactors R1 and R2
• at least three polymerization reactors R1, R2 and R3
• propylene optionally in the presence of low amounts of ethylene is polymerized to the polypropylene (Pre-PP).
• the (main) polymerization i.e. the polymerization in the at least two polymerization reactors (R1 and R2), preferably in the at least three polymerization reactors (R1, R2 and R3), is described and subsequently the optional pre-polymerization in the pre-polymerization reactor (PR) prior to the (main) polymerization is defined.
• the process for the (main) preparation of polypropylene (PP) comprises a sequential polymerization process comprising at least two polymerization reactors (R1 and R2).
• the sequential polymerization process comprises at least three polymerization reactors (R1, R2 and R3), more preferably consists of three polymerization reactors (R1, R2 and R3).
• the term “sequential polymerization process” indicates that the polypropylene is produced in at least two polymerization reactors (R1 and R2), preferably in at least three polymerization reactors (R1, R2 and R3), connected in series. Accordingly the present process preferably comprises at least a first polymerization reactor (R1), a second polymerization reactor (R2), and optionally a third polymerization reactor (R3).
• the term “polymerization reactor” shall indicate that the main polymerization takes place. That means the expression “polymerization reactor” (or the term “(polymerization) reactors R1, R2 and R3”) does not include the pre-polymerization reactor which is employed according to a preferred embodiment of the present invention.
• the polypropylene (PP) is produced in the at least two polymerization reactors (R1 and R2), preferably in the at least three polymerization reactors (R1, R2, and R3), more preferably in the three polymerization reactors (R1, R2, and R3).
• the polypropylene (PP) according to this invention preferably comprises at least two fractions (PP-A and PP-B), more preferably consists of two fractions (PP-A and PP-B), still more preferably comprises at least three fractions (PP-A, PP-B and PP-C), yet more preferably consists of three fractions (PP-A, PP-B and PP-C).
• these fractions differ in at least one property, preferably in the molecular weight and thus in the melt flow rate (see below).
• the melt flow rate of the polypropylene fraction (PP-A) obtained in the first polymerization reactor is higher than the melt flow rate of the polypropylene (PP) obtained as the final product.
• polypropylene may comprise also low amounts of a polypropylene (Pre-PP), in case that the overall process comprises also pre-polymerization as defined below.
• Pre-PP polypropylene
• the first polymerization reactor (R1) is preferably a slurry reactor (SR) and can be any continuous or simple stirred batch tank reactor or loop reactor operating in bulk or slurry.
• Bulk means a polymerization in a reaction medium that comprises of at least 60% (w/w) monomer.
• the slurry reactor (SR) is preferably a (bulk) loop reactor (LR).
• this first polymerization reactor (R1) at least the Ziegler-Natta catalyst (ZN-C) and propylene (C3) is fed.
• the Ziegler-Natta catalyst (ZN-C) is fed as the mixture (MI) of the Ziegler-Natta catalyst (ZN-C) and the polypropylene (Pre-PP) produced in the pre-polymerization reactor (PR) (see below) or is fed directly without pre-polymerization step.
• the Ziegler-Natta catalyst (ZN-C) can be added as such or, preferred, as a mixture of the Ziegler-Natta catalyst (ZN-C) and a polyolefin, preferably a polypropylene.
• Such a mixture may be obtained in a similar manner as the mixture (MI) of the Ziegler-Natta catalyst (ZN-C) and the polypropylene (Pre-PP) is produced.
• This kind of direct feed is described in EP 887379 A, EP 887380 A, EP 887381 A and EP 991684 A.
• direct feed is meant a process wherein the content of the first reactor (R1), i.e. of the loop reactor (LR), the polymer slurry comprising the first polypropylene fraction (PP-A) of the polypropylene (PP), is led directly to the next stage gas phase reactor.
• the polypropylene (PP), i.e. the first polypropylene fraction (PP-A) of the polypropylene (PP), of the first polymerization reactor (R1), more preferably polymer slurry of the loop reactor (LR) containing the first polypropylene fraction (PP-A) of the polypropylene (PP), may be also directed into a flash step or through a further concentration step before fed into the second polymerization reactor (R2), e.g. into the first gas phase reactor (GPR-1).
• this “indirect feed” refers to a process wherein the content of the first polymerization reactor (R1), of the loop reactor (LR), i.e. the polymer slurry, is fed into the second reactor (R2), e.g. into the first gas phase reactor (GPR-1), via a reaction medium separation unit and the reaction medium as a gas from the separation unit.
• a gas phase reactor (GPR) according to this invention is preferably a fluidized bed reactor, a fast fluidized bed reactor or a settled bed reactor or any combination thereof.
• the second polymerization reactor (R2), the third polymerization reactor (R3) and any subsequent polymerization reactor, if present, are preferably gas phase reactors (GPRs).
• gas phase reactors (GPR) can be any mechanically mixed or fluid bed reactors.
• the gas phase reactors (GPRs) comprise a mechanically agitated fluid bed reactor with gas velocities of at least 0.2 m/sec.
• the gas phase reactor is a fluidized bed type reactor preferably with a mechanical stirrer.
• the first polymerization reactor (R1) is a slurry reactor (SR), like loop reactor (LR), whereas the second polymerization reactor (R2), the third polymerization reactor (R3) and any optional subsequent polymerization reactor are gas phase reactors (GPR).
• SR slurry reactor
• GPR gas phase reactor
• at least three polymerization reactor (R1, R2 and R3) preferably three polymerization reactors (R1, R2 and R3), namely a slurry reactor (SR), like a loop reactor (LR), a first gas phase reactor (GPR-1), and a second gas phase reactor (GPR-2) connected in series are used.
• SR slurry reactor
• PR pre-polymerization reactor
• PR pre-polymerization reactor
• the Ziegler-Natta catalyst (ZN-C) is fed into the pre-polymerization reactor (PR), if pre-polymerization is used, and is subsequently transferred with the polypropylene (Pre-PP) obtained in pre-polymerization reactor (PR) into the first reactor (R1).
• a preferred multistage process is a “loop-gas phase”-process, such as developed by Borealis A/S, Denmark (known as BORSTAR® technology) described e.g. in patent literature, such as in EP 0 887 379, WO 92/12182 WO 2004/000899, WO 2004/111095, WO 99/24478, WO 99/24479 or in WO 00/68315.
• a further suitable slurry-gas phase process is the Spheripol® process of Basell.
• the temperature in at least one of the two polymerization reactors (R1 and R2), preferably in at least one of the three polymerization reactors (R1, R2 and R3), more preferably at least in the first polymerization reactor (R1), i.e. in the loop reactor (LR), is in the range of 50 to 130° C., more preferably in the range of 70 to 100° C., still more preferably in the range of 70 to 90° C., yet more preferably in the range of 80 to 90° C., like in the range of 82 to 90° C., i.e. 85° C.
• the process comprises three polymerization reactors (R1, R2 and R3) and in all three polymerization reactors (R1, R2 and R3) the temperature is in the range of 50 to 130° C., more preferably in the range of 70 to 100° C., still more preferably in the range of 70 to 90° C., yet more preferably in the range of 80 to 90° C., like in the range of 82 to 90° C., i.e. 85° C. or 90° C.
• the pressure in the first polymerization reactor (R1) preferably in the loop reactor (LR) is in the range of from 20 to 80 bar, preferably 30 to 60 bar
• the pressure in the second polymerization reactor (R2) i.e. in the first gas phase reactor (GPR-1), and in the third polymerization reactor (R3), i.e. in the second gas phase reactor (GPR-2), and in any subsequent reactor, if present, is in the range of from 5 to 50 bar, preferably 15 to 35 bar.
• the ratio of Ziegler-Natta catalyst (ZN-C) feed rate to propylene (C3) feed rate in the first polymerization reactor (R1) is relatively low, i.e. is 1.0 to 4.5 g/t.
• the ratio of catalyst feed rate to propylene (C3) feed rate in the first polymerization reactor (R1) is 2.0 to 4.0 g/t, more preferably 2.5 to 3.8 g/t, still more preferably 2.5 to 3.5 g/t.
• the propylene (C3) feed rate in the first polymerization reactor (R1) is the sum of the propylene (C3) feed in the pre-polymerization (PR) and the propylene (C3) feed in the first polymerization reactor (R1) together.
• ZN-C Ziegler-Natta catalyst
• the process is carried out such that the melt flow rate MFR 2 measured according to ISO 1133 of the polypropylene (PP-A) produced in the first polymerization reactor (R1) is higher than the polypropylene (PP) obtained as the final product.
• the MFR 2 of polypropylene (PP-A) produced in the first polymerization reactor (R1) is higher than the MFR 2 of the polypropylene (PP) obtained as the final product by at least 1.5 times, more preferably, at least 2 times.
• the weight-ratio of co-catalyst (Co) to propylene (C3) [Co/C3], especially when considering the total propylene feed in the pre-polymerization (if present) and polymerization reactors together is in the range of 15 g/t to 40 g/t, more preferably in the range of 17 g/t to 35 g/t, yet more preferably in the range of 18 g/t to 30 g/t.
• the weight-ratio of external donor (ED) to propylene (C3) [ED/C3], especially when considering the total propylene feed in the pre-polymerization (if present) and polymerization reactors together is in the range of 1.50 g/t to 4.30 g/t, preferably in the range of 2.00 g/t to 4.00 g/t, more preferably in the range of 2.10 g/t to 3.50 g/t.
• the residence time can vary in the reactors identified above.
• the residence time in the first polymerization reactor (R1) for example in the loop reactor (LR)
• the residence time in the subsequent polymerization reactors i.e. in the gas phase reactors generally will be from 0.3 to 8 hours, preferably 0.5 to 4 hours, for example 0.6 to 2 hours.
• the instant process comprises in addition to the (main) polymerization of the polypropylene (PP) in the at least two polymerization reactors (R1 and R2), preferably in the at least three polymerization reactors (R1, R2 and R3), prior thereto a pre-polymerization in a pre-polymerization reactor (PR) upstream to the first polymerization reactor (R1).
• PP polypropylene
• R1 and R2 preferably in the at least three polymerization reactors
• PR pre-polymerization reactor
• a polypropylene (Pre-PP) is produced.
• the pre-polymerization is conducted in the presence of the Ziegler-Natta catalyst (ZN-C).
• ZN-C Ziegler-Natta catalyst
• all the components of the Ziegler-Natta catalyst (ZN-C), i.e. the pro-catalyst (PC), the co-catalyst (Co), and the external donor (ED) are all introduced to the pre-polymerization step.
• the pro-catalyst (PC), the co-catalyst (Co), and the external donor (ED) are only added in the pre-polymerization reactor (PR), if a pre-polymerization is applied.
• ethylene (C3) and ethylene (C2) feed into the pre-polymerization reactor (PR) are used.
• ethylene (C2) is fed to the pre-polymerization reactor (PR) in addition to propylene (C3) in a C2/C3 feed ratio of 0.5 to 10.0 g/kg, preferably of 1.0 to 8.0 g/kg, more preferably of 1.5 to 7.0 g/kg, still more preferably of 2.0 to 6.0 g/kg.
• this feed ratio is used to accomplish a preferred C2/C3 ratio in the pre-polymerization reactor (PR). It is preferred that the C2/C3 ratio in the pre-polymerization reactor (PR) is of 0.5 to 5.0 mol/kmol, preferably of 0.8 to 3.0 mol/kmol, more preferably of 1.0 to 2.0 mol/kmol, still more preferably of 1.1 to 1.8 mol/kmol.
• the weight ratio of the polypropylene (Pre-PP) produced in pre-polymerization reactor (PR) and the transition metal (TM) of the Ziegler-Natta catalyst (ZN-C) is below 4.0 kg Pre-PP/g TM, more preferably in the range of 0.5 to 4.0, still more preferably in the range of 0.8 to 3.0, yet more preferably in the range of 1.0 to 2.5 kg Pre-PP/g TM.
• the weight average molecular weight (M w ) of the polypropylene (Pre-PP) produced in the pre-polymerization reactor (PR) is rather low.
• the polypropylene (Pre-PP) produced in the pre-polymerization reactor (PR) has weight average molecular weight (M w ) of below or equal 300,000 g/mol, more preferably below 200,000 g/mol.
• the weight average molecular weight (M w ) of the polypropylene (Pre-PP) produced in the pre-polymerization reactor (PR) is in the range of 5,000 to 200,000 g/mol, more preferably in the range of 5,000 to 100,000 g/mol, even more preferably in the range of 5,000 to 50,000 g/mol.
• the pre-polymerization reaction is typically conducted at a temperature of 0 to 60° C., preferably from 15 to 50° C., and more preferably from 20 to 45° C.
• the pressure in the pre-polymerization reactor is not critical but must be sufficiently high to maintain the reaction mixture in liquid phase.
• the pressure may be from 20 to 100 bar, for example 30 to 70 bar.
• the pre-polymerization is conducted as bulk slurry polymerization in liquid propylene, i.e. the liquid phase mainly comprises propylene, with optionally inert components dissolved therein.
• an ethylene feed is employed during pre-polymerization as mentioned above.
• Pre-PP polypropylene
• antistatic additive may be used to prevent the particles from adhering to each other or to the walls of the reactor.
• a mixture (MI) of the Ziegler-Natta catalyst (ZN-C) and the polypropylene (Pre-PP) produced in the pre-polymerization reactor (PR) is obtained.
• the Ziegler-Natta catalyst (ZN-C) is (finely) dispersed in the polypropylene (Pre-PP).
• the Ziegler-Natta catalyst (ZN-C) particles introduced in the pre-polymerization reactor (PR) split into smaller fragments which are evenly distributed within the growing polypropylene (Pre-PP).
• the sizes of the introduced Ziegler-Natta catalyst (ZN-C) particles as well as of the obtained fragments are not of essential relevance for the instant invention and within the skilled knowledge.
• the mixture (MI) of the Ziegler-Natta catalyst (ZN-C) and the polypropylene (Pre-PP) produced in the pre-polymerization reactor (PR) is transferred to the first reactor (R1).
• the total amount of the polypropylene (Pre-PP) in the final polypropylene (PP) is rather low and typically not more than 5.0 wt.-%, more preferably not more than 4.0 wt.-%, still more preferably in the range of 0.5 to 4.0 wt.-%, like in the range 1.0 of to 3.0 wt.-%.
• the Ziegler-Natta catalyst (ZN-C) is transferred as a slurry to the first reactor (R1), like loop reactor (LR).
• the slurry contain apart from the Ziegler-Natta catalyst (ZN-C) and the polypropylene (Pre-PP) also to some content un-reacted propylene and ethylene.
• the first reactor (R1) like the loop reactor (LR), may contain some ethylene originally fed to the pre-polymerization reactor (PR).
• the C2/C3 ratio in the first reactor (R1), like loop reactor (LR is of 0.05 to 1.50 mol/kmol, preferably of 0.08 to 1.00 mol/kmol, more preferably of 0.10 to 0.80 mol/kmol, still more preferably of 0.15 to 0.50 mol/kmol, like in the range if 0.30 to 0.50 mol/kmol in case a pre-polymerization step is applied.
• This specific ratio is accomplished preferably without additional ethylene feed in the first reactor (R1), like loop reactor (LR).
• the process according to the instant invention preferably comprises the following steps under the conditions set out above if no pre-polymerization is applied (1 st embodiment)
• the process according the instant invention preferably comprises the following steps under the conditions set out above if a pre-polymerization is used (2 nd embodiment)
• the process according the instant invention preferably comprises the following steps under the conditions set out above if a pre-polymerization is used (3 rd embodiment)
• the polypropylene (PP) is preferably discharged without any washing step. Accordingly in one preferred embodiment the polypropylene (PP) is not subjected to a washing step. In other words in a specific embodiment the polypropylene (PP) is not subjected to a washing step and thus is used unwashed in an application forming process.
• ZN-C Ziegler-Natta catalyst
• the Ziegler-Natta catalyst comprises
• the metal of the compound of a transition metal (TM) is preferably selected from one of the groups 4 to 6, in particular of group 4, like titanium (Ti), of the periodic table (IUPAC). Accordingly the compound of the transition metal (TM) is preferably selected from the group consisting of titanium compound having an oxidation degree of 3 or 4, vanadium compound, chromium compound, zirconium compound, hafnium compound and rare earth metal compounds, more preferably selected from the group consisting of titanium compound, zirconium compound and hafnium compound, and most preferably the transition metal is a titanium compound. Moreover the compounds of the transition metal (TM) are in particular transition metal halides, such as transition metal chlorides. The titanium trichloride and titanium tetrachloride are particularly preferred. Especially preferred is titanium tetrachloride.
• the compound of metal (M) is a compound which metal is selected from one of the groups 1 to 3 of the periodic table (IUPAC), preferably from the Group 2 metal.
• the compound of metal (M) is titanium-less.
• the compound of metal (M) is a magnesium compound, like MgCl 2 .
• the pro-catalyst (PC) comprises an internal electron donor (ID), which is chemically different to the external donor (ED) of the Ziegler-Natta catalyst (ZN-C), i.e. the internal donor (ID) preferably comprises, still more preferably is, a dialkylphthalate of formula (II)
• R 1 and R 2 can be independently selected from a C 1 to C 4 alkyl, preferably R 1 and R 2 are the same, i.e. define the same C 1 to C 4 alkyl residue.
• the internal donor (ID) comprises, like is, a n-dialkylphthalate of formula (II), wherein R 1 and R 2 can be independently selected from a C 1 to C 4 n-alkyl, preferably R 1 and R 2 are the same, i.e. define the same C 1 to C 4 n-alkyl residue.
• the internal donor (ID) comprises, like is, n-dialkylphthalate of formula (II), wherein R 1 and R 2 can be independently selected from a C 1 and C 2 alkyl, preferably R 1 and R 2 are the same, i.e. define the same C 1 or C 2 alkyl residue.
• the internal donor (ID) comprises, like is, diethylphthalate.
• PC pro-catalyst
• the pro-catalyst (PC) contains not more than 2.5 wt.-% of the transition metal (TM), preferably titanium. Still more preferably the pro-catalyst contains 1.7 to 2.5 wt.-% of the transition metal (TM), preferably titanium.
• the molar ratio of internal donor (ID) to metal (M), like Mg, of the pro-catalyst [ID/M] is between 0.03 and 0.08, still more preferably between 0.04 and 0.06, and/or its internal donor (ID) content is between 4 and 15 wt.-%, still more preferably between 6 and 12 wt.-%.
• the internal donor (ID) is the result of a transesterification of a dialkylphthalate of formula (I) with an alcohol.
• the pro-catalyst (PC) is a pro-catalyst (PC) as produced in the patent applications WO 87/07620, WO 92/19653, WO 92/19658 and EP 0 491 566. The content of these documents is herein included by reference.
• the metal of the compound of a transition metal is preferably selected from one of the groups 4 to 6, in particular of group 4, like titanium (Ti), of the periodic table (IUPAC). Accordingly it is preferred that the pro-catalyst (PC) is prepared by bringing together
• dialkylphthalate of formula (I) for the above and further down described process for the manufacture of the pro-catalyst (PC) is selected from the group consisting of propylhexyl phthalate (PrHP), dioctylphthalate (DOP), di-iso-decyl phthalate (DIDP), diundecyl phthalate, diethylhexylphthalate and ditridecyl phthalate (DTDP).
• the most preferred dialkylphthalate is dioctylphthalate (DOP), like di-iso-octylphthalate or diethylhexylphthalate, in particular diethylhexylphthalate.
• dialkylphthalate of formula (I) is transesterified to the dialkylphthalate of formula (II) as defined above.
• PC pro-catalyst
• the Ziegler-Natta catalyst (ZN-C) comprises a co-catalyst (Co).
• the co-catalyst (Co) is a compound of group 13 of the periodic table (IUPAC), e.g. organo aluminium, such as an aluminium compound, like aluminium alkyl, aluminium halide or aluminium alkyl halide compound.
• the co-catalyst (Co) is a trialkylaluminium, like triethylaluminium (TEA), dialkyl aluminium chloride or alkyl aluminium sesquichloride.
• TAA triethylaluminium
• the Ziegler-Natta catalyst (ZN-C) must comprise an external donor (ED).
• the external donor (ED) is a hydrocarbyloxy silane derivative. Accordingly in one specific embodiment the external donor (ED) is represented by formula (IIIa) or (IIIb).
• Formula (IIIa) is defined by Si(OCH 3 ) 2 R 2 5 (IIIa) wherein R 5 represents a branched-alkyl group having 3 to 12 carbon atoms, preferably a branched-alkyl group having 3 to 6 carbon atoms, or a cyclo-alkyl having 4 to 12 carbon atoms, preferably a cyclo-alkyl having 5 to 8 carbon atoms.
• R 5 is selected from the group consisting of iso-propyl, iso-butyl, iso-pentyl, tert.-butyl, tert.-amyl, neopentyl, cyclopentyl, cyclohexyl, methylcyclopentyl and cycloheptyl.
• Formula (IIIb) is defined by Si(OCH 2 CH 3 ) 3 (NR x R y ) (IIIb) wherein R x and R y can be the same or different a represent a hydrocarbon group having 1 to 12 carbon atoms.
• R x and R y are independently selected from the group consisting of linear aliphatic hydrocarbon group having 1 to 12 carbon atoms, branched aliphatic hydrocarbon group having 1 to 12 carbon atoms and cyclic aliphatic hydrocarbon group having 1 to 12 carbon atoms.
• R x and R y are independently selected from the group consisting of methyl, ethyl, n-propyl, n-butyl, octyl, decanyl, iso-propyl, iso-butyl, iso-pentyl, tert.-butyl, tert.-amyl, neopentyl, cyclopentyl, cyclohexyl, methylcyclopentyl and cycloheptyl.
• both R x and R y are the same, yet more preferably both R x and R y are an ethyl group.
• the external donor is selected from the group consisting of diethylaminotriethoxysilane [Si(OCH 2 CH 3 ) 3 (N(CH 2 CH 3 ) 2 )] (U-donor), dicyclopentyl dimethoxy silane [Si(OCH 3 ) 2 (cyclo-pentyl) 2 ] (D-donor), diisopropyl dimethoxy silane [Si(OCH 3 ) 2 (CH(CH 3 ) 2 ) 2 ] (P-donor) and mixtures thereof.
• the external donor is dicyclopentyl dimethoxy silane [Si(OCH 3 ) 2 (cyclo-pentyl) 2 ] (D-donor).
• ZN-C Ziegler-Natta catalyst
• the Ziegler-Natta catalyst is modified by polymerizing a vinyl compound in the presence of said catalyst, wherein the vinyl compound has the formula: CH 2 ⁇ CH—CHR 3 R 4 wherein R 3 and R 4 together form a 5- or 6-membered saturated, unsaturated or aromatic ring or independently represent an alkyl group comprising 1 to 4 carbon atoms.
• PC pro-catalyst
• the co-catalyst (Co) as well as the external donor (ED) are fed to the pre-polymerization reactor.
• a preferred aspect of the present invention is that the ratio between on the one hand of co-catalyst (Co) and the external donor (ED) [Co/ED] and on the other hand of the co-catalyst (Co) and the transition metal (TM) [Co/TM] have been carefully chosen.
• the polypropylene (PP) can be produced with high productivity. Accordingly, the polypropylene (PP) is in particular featured by low ash content, in particular by low ash content without any purification, i.e. washing step. Accordingly the polypropylene (PP) has an ash content of below 40 ppm, i.e. in the range of 10 to below 40 ppm, preferably of below 35 ppm, i.e. 15 to below 35 ppm, more preferably of below 31 ppm, i.e. in the range of 20 to 31 ppm.
• ZN-C Ziegler-Natta catalyst
• any polypropylene (PP) can be produced with the instant process including complex structures, like heterophasic systems, i.e. a composition comprising a polypropylene matrix in which an elastomeric propylene copolymer is dispersed.
• the polypropylene (PP) according to this invention is featured by rather low cold xylene soluble (XCS) content, i.e. by a xylene cold soluble (XCS) of below 10 wt.-%, and thus is not be regarded as a heterophasic system.
• XCS cold xylene soluble
• XCS xylene cold soluble
• the polypropylene (PP) has preferably a xylene cold soluble content (XCS) in the range of 0.3 to 6.0 wt.-%, more preferably 0.5 to 5.5 wt.-%, still more preferably 1.0 to 4.0 wt.-%.
• XCS xylene cold soluble content
• the polypropylene (PP) is preferably a crystalline.
• crystalline indicates that the polypropylene (PP), i.e. the propylene homopolymer (H-PP) or the propylene copolymer (R-PP), has a rather high melting temperature. Accordingly throughout the invention the propylene homopolymer (H-PP) or the propylene copolymer (R-PP) is regarded as crystalline unless otherwise indicated.
• the polypropylene (PP) has preferably a melting temperature more than 120° C., more preferably more than 125° C., still more preferably more than 130° C., like in the range of more than 130 to 168° C., yet more preferably of more than 158° C., like of more than 158 to 168, still yet of more preferably more than 159° C., like of more than 159 to 168° C.
• the melting temperature is especially preferred of more than 158° C., i.e. of more than 158 to 168, like of more than 159° C., i.e. of more than 159 to 168° C.
• the melting temperature is preferably more than 125° C., like in the range of more than 125 to 155° C., more preferably of more than 130° C., like in the range of more than 130 to 155° C.
• the polypropylene (PP), i.e. the propylene homopolymer (H-PP) or the random propylene copolymer (R-PP), has a rather high crystallization temperature.
• the polypropylene (PP), i.e. the propylene homopolymer (H-PP) or the random propylene copolymer (R-PP) has a crystallization temperature of at least 105° C., more preferably of at least 109° C.
• the propylene homopolymer (H-PP) or the random propylene copolymer (R-PP), has a crystallization temperature in the range of 105 to 128° C., more preferably in the range of 109 to 128° C., yet more preferably in the range of 109 to 125° C.
• the crystallization temperature is especially preferred of more than 105° C., i.e. of more than 105 to 128, more preferably of more than 109° C., like of more than 109 to 128° C.
• the crystallization temperature is preferably more than 109° C., like in the range of more than 109 to 120° C., more preferably of more than 110° C., like in the range of more than 110 to 120° C.
• the polypropylene (PP), like the propylene homopolymer (H-PP) or the random propylene copolymer (R-PP), is isotactic. Accordingly it is appreciated that the polypropylene (PP), like the propylene homopolymer (H-PP) or the random propylene copolymer (R-PP), has a rather high pentad concentration (mmmm %) i.e. more than 92.0%, more preferably more than 93.5%, like more than 93.5 to 97.0%, still more preferably at least 94.0%, like in the range of 94.0 to 97.0%.
• mmmm % rather high pentad concentration
• a further characteristic of the polypropylene (PP), like of the propylene homopolymer (H-PP) or of the random propylene copolymer (R-PP), is the low amount of misinsertions of propylene within the polymer chain, which indicates that the polypropylene (PP), like the propylene homopolymer (H-PP) or the random propylene copolymer (R-PP), is produced in the presence of a catalyst as defined above, i.e. in the presence of a Ziegler-Natta catalyst (ZN-C).
• ZN-C Ziegler-Natta catalyst
• the polypropylene (PP), like the propylene homopolymer (H-PP) or the random propylene copolymer (R-PP), is preferably featured by low amount of 2,1 erythro regio-defects, i.e. of equal or below 0.4 mol.-%, more preferably of equal or below than 0.2 mol.-%, like of not more than 0.1 mol.-%, determined by 13 C-NMR spectroscopy. In an especially preferred embodiment no 2,1 erythro regio-defects are detectable.
• the polypropylene (PP) Due to the low amounts of regio-defects the polypropylene (PP) is additionally characterized by a high content of thick lamella.
• the specific combination of rather high mmmm pentad concentration and low amount of regio-defects has also impact on the crystallization behaviour of the polypropylene (PP).
• the polypropylene (PP), like of the propylene homopolymer (H-PP) or of the random propylene copolymer (R-PP), of the instant invention is featured by long crystallisable sequences and thus by a rather high amount of thick lamellae.
• SIST stepwise isothermal segregation technique
• the polypropylene (PP), like of the propylene homopolymer (H-PP) or of the random propylene copolymer (R-PP), can be additionally or alternatively defined by the crystalline fractions melting in the temperature range of above 170 to 180° C. Accordingly it is preferred that the polypropylene (PP), like of the propylene homopolymer (H-PP) or of the random propylene copolymer (R-PP), has a crystalline fraction melting above 170 to 180° C.
• the polypropylene (PP), like of the propylene homopolymer (H-PP) or of the random propylene copolymer (R-PP), has a crystalline fraction melting above 160 to 170° C. of more than 36.0 wt.-%, more preferably in the range of more than 36.0 to equal or below 45.0 wt.-%, still more preferably in the range of more than 38.0 to 43.0 wt.-% wherein said fraction is determined by the stepwise isothermal segregation technique (SIST).
• SIST stepwise isothermal segregation technique
• the values provided for the pentad concentration, the 2,1 erythro regio-defects, and crystalline fractions obtained by SIST are especially applicable in case the polypropylene (PP) is a propylene homopolymer (H-PP).
• polypropylene especially the propylene homopolymer (H-PP)
• XCS xylene cold soluble content
• the polypropylene (PP), like the propylene homopolymer (H-PP) or the random propylene copolymer (R-PP), has an MFR 2 (230° C.) of equal or below 7.0 g/10 min, more preferably in the range of 0.5 to 7.0 g/10 min, like in the range of 1.5 to 7.0 g/10 min, yet more preferably in the range of 1.0 to 5.0 g/10 min, still more preferably in the range of 1.5 to 4.0 g/10 min.
• the polypropylene (PP), like the propylene homopolymer (H-PP) or the random propylene copolymer (R-PP), is defined by its crossover frequency ⁇ c (a parameter corresponding to the weight average molecular weight), said crossover frequency ⁇ c is the frequency at which the storage modulus G′ and the loss modulus G′′ determined in a dynamic-mechanical rheology test are identical and defined as crossover modulus G.
• the polypropylene (PP), like the propylene homopolymer (H-PP) or the random propylene copolymer (R-PP) has a crossover frequency ⁇ c as determined by dynamic rheology according to ISO 6271-10 at 200° C.
• the polypropylene (PP), like the propylene homopolymer (H-PP) or the random propylene copolymer (R-PP), is featured by a moderate molecular weight distribution. Accordingly it is required that the polypropylene (PP), like the propylene homopolymer (H-PP) or the random propylene copolymer (R-PP), has a polydispersity index (PI), defined as 10 5 /G c with G c being the crossover modulus from dynamic rheology according to ISO 6271-10 at 200° C., of at least 2.5, more preferably in the range of 2.5 to below 5.5, still more preferably in the range of 3.0 to 5.0, like 3.4 to 4.5.
• PI polydispersity index
• the polypropylene (PP), like the propylene homopolymer (H-PP) or the random propylene copolymer (R-PP), has a shear thinning index SHI (0/100) measured according to ISO 6271-10 at 200° C. of at least 20, more preferably of at least 22, yet more preferably in the range of 20 to below 50, still more preferably in the range of 22 to 45, like in the range of 25 to 40 or in the range of 28 to 45.
• the polypropylene (PP) is a propylene homopolymer (H-PP).
• polypropylene homopolymer relates to a polypropylene that consists substantially, i.e. of at least 99.0 wt.-%, more preferably of at least 99.5 wt.-%, of propylene units.
• ethylene is fed in a pre-polymerization reactor (PR). From this polymerization reactor (PR) un-reacted ethylene may be transferred to the first reactor (R1), like loop reactor (LR).
• R1 pre-polymerization reactor
• LR loop reactor
• the polypropylene (Pre-PP) as well as the first polypropylene fraction (PP-A) contain ethylene and thus also to some extent the final polypropylene (PP).
• the final polypropylene (PP) being a polypropylene homopolymer (H-PP) may contain ethylene in a measurable amount.
• the polypropylene homopolymer (H-PP) according to the present invention may comprise ethylene units in an amount of up to 0.90 wt.-%, preferably up to 0.80 wt.-%, more preferably in the range of 0.20 to 0.70 wt.-%, yet more preferably in the range of 0.20 to 0.60 wt.-%.
• the polypropylene (PP) is a random polypropylene copolymer (R-PP), it comprises monomers copolymerizable with propylene, i.e. ⁇ -olefins other than propylene, for example comonomers such as ethylene and/or C 4 to C 10 ⁇ -olefins, in particular ethylene and/or C 4 to C 8 ⁇ -olefins, e.g. 1-butene and/or 1-hexene.
• the random polypropylene copolymer (R-PP) comprises, especially consists of, monomers copolymerizable with propylene from the group consisting of ethylene, 1-butene and 1-hexene.
• the random polypropylene copolymer (R-PP) comprises—apart from propylene—units derivable from ethylene and/or 1-butene.
• the random polypropylene copolymer (R-PP) comprises units derivable from ethylene and propylene only.
• the comonomer content in the random polypropylene copolymer (R-PP) is preferably relatively low, i.e. below 10.0 wt.-% or more preferably equal or below 5.0 wt.-%.
• the comonomer content is preferably above 0.7 to 5.0 wt.-%, more preferably in the range of above 0.8 to 4.0 wt.-%, even more preferably in the range of above 0.9 to 3.5 wt.-% and most preferably in the range of 1.0 to 3.0 wt.-%, based on the total weight of the random polypropylene copolymer (R-PP).
• random is understood according to IUPAC (Glossary of basic terms in polymer science; IUPAC recommendations 1996). Accordingly it is preferred that the random polypropylene copolymer (R-PP) has a randomness of at least 40%, more preferably of at least 50%, yet more preferably at least 55%, even more preferably of at least 60%, and still more preferably of at least 65%.
• the instant polypropylene (PP), like the propylene homopolymer (H-PP) or the random propylene copolymer (R-PP), are produced in at least two reactors, preferably in three reactors.
• the instant polypropylene (PP), like the propylene homopolymer (H-PP) or the random propylene copolymer (R-PP) comprises or consists of, preferably three fractions (apart from the polypropylene (Pre-PP)).
• the polypropylene (PP), like the propylene homopolymer (H-PP) or the random propylene copolymer (R-PP) comprises
• polypropylene is a propylene homopolymer (H-PP) also its fractions are propylene homopolymer fractions.
• the polypropylene (PP) according to the present invention comprises individual fractions that differ in the melt flow rate MFR 2 . If there are substantial differences in the melt flow rates of the individual fractions, the polypropylene (PP) is referred to as multimodal, such as bimodal ((PP-A) and (PP-B)) or trimodal ((PP-A), (PP-B), and (PP-C)), depending on the number of fractions having different melt flow rates.
• the polypropylene (PP) is a multimodal propylene homopolymer (H-PP) or a multimodal random propylene copolymer (R-PP), preferably a multimodal propylene homopolymer (H-PP), wherein each polypropylene fraction present, preferably each of the polypropylene fractions (PP-A), (PP-B), and (PP-C), has a different melt flow rate MFR 2 , i.e.
• g/10 min differ by more than +/ ⁇ 1.3 g/10 min, more preferably differ by more than +/ ⁇ 1.5 g/10 min, still more preferably differ from by more than 1.3 g/10 min to not more than +/ ⁇ 7.0 g/10 min, yet more preferably differ from by more than 1.5 g/10 min to not more than +/ ⁇ 6.5 g/10 min, from each other.
• melt flow rate MFR 2 of the first polypropylene fraction (PP-A), i.e. the polypropylene fraction produced in the first reactor (R1), has a higher melt flow rate than the melt flow rate MFR 2 of the polypropylene (PP).
• melt flow rate MFR 2 of the first polypropylene fraction (PP-A) i.e.
• the polypropylene fraction produced in the first reactor (R1) is by more than 2.5 g/10 min, more preferably by more than 3.0 g/10 min, still more preferably by more than 2.5 g/10 min to not more than 10.0 g/10 min, yet more preferably differ from by more than 3.0 g/10 min to not more than 8.0 g/10 min, higher than the melt flow rate MFR 2 of the polypropylene (PP) obtained as the final product.
• the first polypropylene fraction (PP-A) has the highest melt flow rate MFR 2 of all polypropylene fractions produced in the polymerization reactors (R1, R2 and R3), preferably of all three polypropylene fractions (PP-A), (PP-B), and (PP-C), wherein preferably the first polypropylene fraction (PP-A) is produced in the first polymerization reactor (R1) and the second polypropylene fraction (PP-B) and third polypropylene fraction (PP-C) are produced in the second and third reactors (R2 and R3), preferably in this order.
• the polypropylene (PP) consists of the three polypropylene fractions (PP-A), (PP-B), and (PP-C).
• the wording consisting of shall exclude neither the presence of the polypropylene (Pre-PP) nor the presence of additives but shall rather indicate that no other polypropylene fractions are present.
• the polypropylene (PP) consists of the three polypropylene fractions (PP-A), (PP-B), and (PP-C).
• the wording consisting of shall exclude neither the presence of the polypropylene (Pre-PP) nor the presence of additives but shall rather indicate that no other polypropylene fractions are present.
• the polypropylene (PP) is produced in a process comprising a pre-polymerization process in which ethylene is fed in, the polypropylene (Pre-PP), the first polypropylene fraction (PP-A) and thus also final polypropylene (PP) can contain ethylene in a measurable amount.
• the final polypropylene (PP) being a propylene homopolymer (H-PP) contains ethylene in amount up to 0.9, preferably up to 0.8 wt.-%, such as 0.2 to 0.7 wt.-%, based on the total weight of the final polypropylene (PP), i.e. based on the propylene homopolymer (H-PP).
• the first polypropylene fraction (PP-A) is an ethylene-propylene copolymer fraction (E-PP-A) having ethylene content of at least 0.50 wt.-%, more preferably in the range of 0.50 to 5.00 wt.-%, more preferably in the range of 0.80 to 3.50 wt.-%, still more preferably in the range of 1.00 to 2.50 w.-%.
• the first polypropylene fraction is preferably a propylene homopolymer fraction (H-PP-A).
• propylene homopolymer (H-PP) as mentioned above does not exclude the option that some fractions thereof are propylene copolymers. Even more preferred the propylene homopolymer (H-PP) comprises a first propylene homopolymer fraction (H-PP-A) or an ethylene-propylene copolymer fraction (E-PP-A), the latter preferred, and a second propylene homopolymer fraction (H-PP-B) and a third propylene homopolymer fraction (H-PP-C). Thus in one specific embodiment the propylene homopolymer (H-PP) comprise
• the first polypropylene fraction (PP-A) of a multimodal propylene polymer (PP), preferably the first propylene homopolymer fraction (H-PP-A) or the ethylene-propylene copolymer fraction (E-PP-A), has a melt flow rate (MFR 2 ) measured according to ISO 1133 in the range of 0.5 to 12.0 g/10 min, preferably in the range of 5.0 to 12.0 g/10 min and optionally the second polypropylene fraction (PP-B), preferably the second propylene homopolymer fraction (H-PP-B), has a melt flow rate (MFR 2 ) measured according to ISO 1133 of in the range of 0.05 to 5.0 g/10 min, preferably in the range of 0.05 to 2.0 g/10 min.
• MFR 2 melt flow rate measured according to ISO 1133
• the third polypropylene fraction (PP-C), preferably the third propylene homopolymer fraction (H-PP-C), has a melt flow rate (MFR 2 ) measured according to ISO 1133 of in the range of 1.0 to 7.0 g/10 min, preferably in the range of 2.0 to 6.0 g/10 min.
• the first polypropylene fraction (PP-A), preferably the first propylene homopolymer fraction (H-PP-A) or the ethylene-propylene copolymer fraction (E-PP-A), is produced in the first reactor (R1), preferably in the loop reactor, whereas the second polypropylene fraction (PP-B), preferably the second propylene homopolymer fraction (H-PP-B), is produced in the second reactor (R2), preferably in the first gas phase reactor (GPR-1).
• the third polypropylene fraction (PP-C), preferably the third propylene homopolymer fraction (H-PP-C) is produced in the third reactor (R2), preferably in the second gas phase reactor (GPR-2).
• the polypropylene (PP) is a random propylene copolymer (R-PP) or at least one of the fractions is a random propylene copolymer fraction.
• a random propylene copolymer (R-PP) may also comprise a propylene homopolymer fraction.
• the random propylene copolymer (R-PP) consists of random propylene copolymer fractions only.
• the random propylene copolymer (R-PP) has a higher comonomer content, preferably ethylene content, i.e. preferably in the range of 1.0 to 10.0 wt.-%, more preferably in the range of 1.0 to 5.0 wt.-%, like in the range of 1.0 to 3.0 wt.-%.
• the present invention is directed to a polypropylene (PP) being at least a trimodal propylene homopolymer (H-PP), preferably is a trimodal propylene homopolymer (H-PP), having
• each of the polypropylene fractions (PP-A), (H-PP-B), and (H-PP-C) has a different melt flow rate MFR 2 , i.e. differ by more than +/ ⁇ 1.3 g/10 min, more preferably differ by more than +/ ⁇ 1.5 g/10 min, still more preferably differ from by more than 1.3 g/10 min to not more than +/ ⁇ 7.0 g/10 min, yet more preferably differ from by more than 1.5 g/10 min to not more than +/ ⁇ 6.5 g/10 min, from each other.
• the at least trimodal propylene homopolymer e.g. the trimodal propylene homopolymer (H-PP)
• H-PP has an ethylene content up to 0.90 wt.-%, preferably up to 0.80 wt.-%, more preferably in the range of 0.20 to 0.70 wt.-%, yet more preferably in the range of 0.20 to 0.60 wt.-%.
• No other comonomers are present in the at least trimodal propylene homopolymer (H-PP).
• the first polypropylene fraction (PP-A) of the at least trimodal propylene homopolymer (H-PP), e.g. the trimodal propylene homopolymer (H-PP), is an ethylene-propylene copolymer fraction (E-PP-A) having ethylene content of more than 0.5 wt.-% to 5.0 wt.-%, more preferably between 0.80 wt.-% and 3.50 wt.-%, still more preferably between 1.0 wt.-% and 2.50 wt.-%, based on the total weight of the first polypropylene fraction (PP-A).
• propylene homopolymers (H-PP) of the previous paragraph i.e. the trimodal propylene homopolymer (H-PP), e.g. the trimodal propylene homopolymer (H-PP), have further
• propylene homopolymer (H-PP) can be taken from the information provided for the polypropylene (PP) discussed above. Accordingly all preferred embodiments for the polypropylene (PP) are also preferred embodiments of the propylene homopolymer (H-PP) if not otherwise indicated. Further, all preferred embodiments of the described polypropylene (PP) and propylene homopolymer (H-PP), respectively, are also preferred products of the defined process of the instant invention.
• the polypropylene (PP), especially the propylene homopolymer (H-PP), as defined can subjected to a film forming process obtaining thereby a capacitor film.
• the polypropylene (PP), especially the propylene homopolymer (H-PP) is the only polymer within the capacitor film.
• the capacitor film may contain additives but preferably no other polymer.
• the remaining part up to 100.0 wt-% may be accomplished by additives known in the art, like antioxidants. However this remaining part shall be not more than 5.0 wt.-%, preferably not more than 2.0 wt.-%, like not more than 1.0 wt. %, within the capacitor film.
• the capacitor film preferably comprises more than 95.0 wt.-%, more preferably more 98.0 wt.-%, like more than 99.0 wt.-%, of the polypropylene (PP), especially the propylene homopolymer (H-PP), as defined herein.
• PP polypropylene
• H-PP propylene homopolymer
• the thickness of the capacitor film can be up to 15.0 ⁇ m, however, typically the capacitor film has a thickness of not more than 12.0 ⁇ m, preferably not more than 10.0 ⁇ m, more preferably not more than 8.0 ⁇ m, yet more preferably in the range of 2.5 to 10 ⁇ m, like in the range of 3.0 to 8.0 ⁇ m.
• the capacitor film is a biaxially oriented film, i.e. the polypropylene (PP), especially the propylene homopolymer (H-PP), as defined above or any mixtures (blends) comprising the polypropylene (PP), especially comprising the propylene homopolymer (H-PP), has/have been subjected to a drawing process obtaining thereby a biaxially oriented polymer.
• capacitor film preferably contains the polypropylene (PP), especially the propylene homopolymer (H-PP), as only polymer and thus it is preferably a biaxially oriented polypropylene (BOPP) made from said polypropylene (PP), especially made from said propylene homopolymer (H-PP).
• the capacitor film i.e. the biaxially oriented polypropylene (BOPP)
• BOPP biaxially oriented polypropylene
• the capacitor film has a draw ratio in machine direction of at least 3.0 and a draw ratio in transverse direction of at least 3.0.
• Such ratios are appreciated as commercial biaxially oriented polypropylene films must be stretchable at least to the above defined extent without breaking.
• the length of the sample increases during stretching in longitudinal direction and the draw ratio in longitudinal direction calculates from the ratio of current length over original sample length. Subsequently, the sample is stretched in transverse direction where the width of the sample is increasing. Hence, the draw ratio calculates from the current width of the sample over the original width of the sample.
• the draw ratio in machine direction of the capacitor film i.e.
• biaxially oriented polypropylene ranges from 3.5 to 8.0, more preferably from 4.5 to 6.5.
• the draw ratio in transverse direction of the capacitor film, i.e. of the biaxially polypropylene (BOPP) ranges preferably from 4.0 to 15.0, more preferably from 6.0 to 10.0.
• Temperature range during stretching is in general 100° C. to 180° C.
• the capacitor film i.e. the biaxially oriented polypropylene (BOPP), preferably is produced from the polypropylene (PP), especially from the propylene homopolymer (H-PP), as defined above, the properties given for the polypropylene (PP), especially for the propylene homopolymer (H-PP), are equally applicable for the capacitor film if not specified differently.
• PP polypropylene
• H-PP propylene homopolymer
• the polypropylene (PP), especially the propylene homopolymer (H-PP), is biaxially oriented.
• the polypropylene (PP) is subjected to a film forming process. Any film forming processes which are suitable for the manufacture of a capacitor film can be used.
• the polypropylene (PP) is not subjected to a washing step prior to the film forming process.
• the capacitor film i.e. the biaxially oriented polypropylene (BOPP)
• BOPP biaxially oriented polypropylene
• the process for the manufacture of a capacitor film, i.e. the biaxially oriented polypropylene (BOPP) comprises the use of the polypropylene (PP) as defined herein and its forming into a film preferably by the tenter method known in the art.
• the tenter method is in particular a method in which the polypropylene (PP), especially the propylene homopolymer (H-PP), as defined herein is melt extruded from a slit die such as a T-die and cooled on a cooling drum obtaining an undrawn sheet.
• Said sheet is pre-heated for example with a heated metal roll and then drawn in the length direction between a plurality of rolls over which a difference in peripheral speeds is established and then both edges are gripped with grippers and the sheet is drawn in the transverse direction in an oven by means of a tenter resulting in a biaxially drawn film.
• the temperature of said stretched sheet during the longitudinal drawing is preferably controlled in such a way as to be within the temperature range of the melting point of the polypropylene as defined herein (machine direction: ⁇ 20 to ⁇ 10° C.; transverse direction: ⁇ 5 to +10° C.).
• the uniformity of the film thickness on transverse drawing can be evaluated with the method in which a fixed region on the film is masked after drawing in the length direction and measuring the actual drawing factor by measuring the spacing of the said masking after transverse drawing.
• the capacitor film i.e. the biaxially oriented film (BOPP)
• the capacitor film can be treated by corona discharge in air, nitrogen, carbon dioxide gas or any of the mixtures on the surface to be metalized, to improve the adhesive strength to the metal to be deposited, and wound by a winder.
• BOPP biaxially oriented film
• Quantitative nuclear-magnetic resonance (NMR) spectroscopy was used to quantify the stereo-regularity (tacticity), regio-regularity and comonomer content of the polymers.
• Quantitative 13 C ⁇ 1 H ⁇ NMR spectra were recorded in the solution-state using a Bruker Advance III 400 NMR spectrometer operating at 400.15 and 100.62 MHz for 1 H and 13 C respectively. All spectra were recorded using a 13 C optimised 10 mm extended temperature probehead at 125° C. using nitrogen gas for all pneumatics.
• TCE-d 2 1,2-tetrachloroethane-d 2
• TCE-d 2 1,2-tetrachloroethane-d 2
• the NMR tube was further heated in a rotary oven for at least 1 hour. Upon insertion into the magnet the tube was spun at 10 Hz.
• This setup was chosen primarily for the high resolution needed for tacticity distribution quantification (Busico, V., Cipullo, R., Prog. Polym. Sci. 26 (2001) 443; Busico, V.; Cipullo, R., Monaco, G., Vacatello, M., Segre, A. L., Macromolecules 30 (1997) 6251).
• Standard single-pulse excitation was employed utilising the NOE and bi-level WALTZ16 decoupling scheme (Zhou, Z., Kuemmerle, R., Qiu, X., Redwine, D., Cong, R., Taha, A., Baugh, D. Winniford, B., J. Mag. Reson. 187 (2007) 225; Busico, V., Carbonniere, P., Cipullo, R., Pellecchia, R., Severn, J., Talarico, G., Macromol. Rapid Commun. 2007, 28, 11289).
• a total of 8192 (8 k) transients were acquired per spectra
• Quantitative 13 C ⁇ 1 H ⁇ NMR spectra were processed, integrated and relevant quantitative properties determined from the integrals using proprietary computer programs.
• the tacticity distribution was quantified through integration of the methyl region between 23.6-19.7 ppm correcting for any sites not related to the stereo sequences of interest (Busico, V., Cipullo, R., Prog. Polym. Sci. 26 (2001) 443; Busico, V., Cipullo, R., Monaco, G., Vacatello, M., Segre, A. L., Macromolecules 30 (1997) 6251).
• the mole fraction of ethylene in the polymer was quantified using the method of Wang et. al. (Wang, W-J., Zhu, S., Macromolecules 33 (2000), 1157) through integration of multiple signals across the whole spectral region of a 13 C ⁇ 1 H ⁇ spectra acquired using defined conditions. This method was chosen for its accuracy, robust nature and ability to account for the presence of regio-defects when needed. Integral regions were slightly adjusted to increase applicability to a wider range of comonomer contents.
• the comonomer sequence distribution at the triad level was determined using the method of Kakugo et al. (Kakugo, M., Naito, Y., Mizunuma, K., Miyatake, T. Macromolecules 15 (1982) 1150) through integration of multiple signals across the whole spectral region of a 13 C ⁇ 1 H ⁇ spectra acquired using defined conditions. This method was chosen for its robust nature. Integral regions were slightly adjusted to increase applicability to a wider range of comonomer contents.
• Shear thinning indexes which are correlating with MWD and are independent of MW, were calculated according to Heino 1,2 ) (below).
• the SHI (0/100) is defined as the ratio between the zero shear viscosity and the viscosity at the shear stress of a shear stress of 100 kPa ( ⁇ *100).
• melt flow rates were measured with a load of 2.16 kg (MFR 2 ) at 230° C.
• the melt flow rate is that quantity of polymer in grams which the test apparatus standardized to ISO 1133 extrudes within 10 minutes at a temperature of 230° C. under a load of 2.16 kg.
• MFR ⁇ ( PP ⁇ ⁇ 2 ) 10 [ l ⁇ ⁇ og ⁇ ( MFR ⁇ ( R ⁇ ⁇ 2 ) ) - w ⁇ ( PP ⁇ ⁇ 1 ) ⁇ l ⁇ ⁇ og ⁇ ( MFR ⁇ ( PP ⁇ ⁇ 1 ) ) w ⁇ ( PP ⁇ ⁇ 2 ) ] wherein
• MFR ⁇ ( PP ⁇ ⁇ 3 ) 10 [ l ⁇ ⁇ og ⁇ ( MFR ⁇ ( R ⁇ ⁇ 3 ) ) - w ⁇ ( R ⁇ ⁇ 2 ) ⁇ l ⁇ ⁇ og ⁇ ( MFR ⁇ ( R ⁇ ⁇ 2 ) ) w ⁇ ( PP ⁇ ⁇ 3 ) ] wherein
• M n Number average molecular weight (M n ), weight average molecular weight (M w ) and molecular weight distribution (MWD) are determined by Gel Permeation Chromatography (GPC) according to the following method:
• a Waters Alliance GPCV 2000 instrument equipped with refractive index detector and online viscosimeter was used with 3 ⁇ TSK-gel columns (GMHXL-HT) from TosoHaas and 1,2,4-trichlorobenzene (TCB, stabilized with 200 mg/L 2,6-Di tert butyl-4-methyl-phenol) as solvent at 145° C. and at a constant flow rate of 1 mL/min.
• sample solution 216.5 ⁇ L were injected per analysis.
• the column set was calibrated using relative calibration with 19 narrow MWD polystyrene (PS) standards in the range of 0.5 kg/mol to 11 500 kg/mol and a set of well characterized broad polypropylene standards. All samples were prepared by dissolving 5-10 mg of polymer in 10 mL (at 160° C.) of stabilized TCB (same as mobile phase) and keeping for 3 hours with continuous shaking prior sampling in into the GPC instrument.
• PS polystyrene
• the ash content is measured according to ISO 3451-1 (1997).
• ICP Inductively coupled plasma emission spectrometry
• Titanium, aluminium and magnesium in pellets are determined with ICP. Acid standards are used as reference.
• sample weight [g] are first ashed following DIN EN ISO 3451-1 and the ash is dissolved in H 2 SO 4 1N (sample conc. [mg/l])
• the obtained results of the standard low concentration and standard high concentration are inspected in the calibration summary.
• the “RSD value” (relative standard deviation value) of the standard should always be ⁇ 10%.
• the obtained results must be close to the real value of the standards used.
• the calibration summary is checked.
• the correlation coefficient must be ⁇ 13.997.
• the samples are analysed 3 times each. The obtained results are checked and ensured that the RSD ⁇ 10%.
• xylene solubles (XCS, wt.-%): Content of xylene cold solubles (XCS) is determined at 25° C. according ISO 16152; first edition; 2005-07-01.
• melt- and crystallization enthalpy (H m and H c ) were measured by the DSC method according to ISO 11357-3.
• the isothermal crystallisation for SIST analysis was performed in a Mettler TA820 DSC on 3 ⁇ 0.5 mg samples at decreasing temperatures between 200° C. and 105° C.
• the sample was cooled down with 80° C./min to ⁇ 10° C. and the melting curve was obtained by heating the cooled sample at a heating rate of 10° C./min up to 200° C. All measurements were performed in a nitrogen atmosphere.
• the melt enthalpy is recorded as function of temperature and evaluated through measuring the melt enthalpy of fractions melting within temperature intervals of
• the catalyst used in the polymerization process for examples IE1, IE2, IE3, CE1 and CE2 has been produced as follows: First, 0.1 mol of MgCl 2 ⁇ 3 EtOH was suspended under inert conditions in 250 ml of decane in a reactor at atmospheric pressure. The solution was cooled to the temperature of ⁇ 15° C. and 300 ml of cold TiCl 4 was added while maintaining the temperature at said level. Then, the temperature of the slurry was increased slowly to 20° C. At this temperature, 0.02 mol of dioctylphthalate (DOP) was added to the slurry. After the addition of the phthalate, the temperature was raised to 135° C. during 90 minutes and the slurry was allowed to stand for 60 minutes.
• DOP dioctylphthalate
• polypropylene polymers can be manufactured according to the present invention with increased productivity and thus a lower ash content.
• Inventive example IE1 shows in comparison to comparative examples CE1 to CE3 a significant increase in productivity per catalyst.
• IE1 a lower catalyst to propylene (C3) feed ratio was employed in the first polymerization reactor (R1).
• the resulting polymer produced according to IE1 consequently shows a lower impurity content as e.g. evident from the ash content.
• IE2 to IE4 further demonstrate in comparison to CE1 to CE3 and IE1 the additional effect of the polymer design on catalyst productivity.
• the propylene polymer (PP-A) produced in the first polymerization reactor (R1) has a higher MFR 2 as the propylene polymer (PP) obtained as the final product in the third polymerization reactor (R3).
• the degree of impurities is further reduced in IE2 to IE4 as can be seen e.g. from the ash content.

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